Process of refining lubricating-oils.



H. T. MAITLAND.

PROCESS OF REFINING LUBRICATING OILS.

APPLICATION FILED AUG.5| I915.

Patented June 27, 1916.

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sans PATENT clarion.

'- HAROLD 'r. MAITLAND, 0F MARCUS Hook, PnNNsYLvANIA, ASSIGNOR 'ro sUN COMPANY, or PHILADELPHIA, PENNSYLVANIA, A'CORPORATION on NEW JERSEY.

and useful Improvement in Processes of Refining Lubricating-Oilsof which the following is a full, clear, and exact description.

.My invention relates to the refining of lubricating oils and has for its more especial object the production of an oil of a color best adapted for sale as a commercial product. j

- In the refiningof petroleum oil distillates, especially the lighter distillates adapted for illuminating purposes, it is customary to .add to the same, sulfuricacid in an amount dependent upon the character of the distillate, thoroughly mix the oil and acid by agitati0n,;and. allow the mixture to settle. The result of this treatment is to cause the acid to combine with certain hydrocarbons and other compounds, the removalof which hydrocarbons and other compounds renders the remaining oil of greater purity and better color. The-combined acid hydrocarbons and. compounds then settle to the bottom of the tank, forming a sludge acid wh1ch 1s drawn ofl. The oil is then washed with water, which is then allowed to settle and is drawn oil, the washing operation being repeated as often as is necessary. An alkali,

usually caustic soda, is added to neutralize the acid and thus eliminate'it, as fully as possible, fronr' the oil, after which the 011 may be again washed by agitating. Alkalis other than caustic soda, have been used, and

- in the manufacture of illuminating oils and in the treatment of sludge," aqua ammonia and other alkaline substances have been mentioned in prior patents as substitutes for the caustic soda. The sulfuric acid process, followed by treatment with caustic soda,

- has also been applied to the refining of the heavier distillates and reduced distillates such as those adapted for lubricating purposes. But this treatment, as applied to lubricating oils, has not produced satisfacxtory results. The oil, after distillation, is

much darker in color than the lighter distillates, due to the presence of comparatively large quantities of certain hydrocarbons and compounds which render'the oil PROCESS OF REFINING LUBRICATING-OILS.

Specification of Letters Patent. Patentefl n 7, 11916, Application filed August 5, 1915. Serial 0. 43,738.

Owing to the finelyusual method is to allow the oil containing I these resins to remain in a state of quiescence in a settling container until a large part of the resms has been settled to the bottom of the containenfrom which they weredrawn off by means of a pipe connected to the bottom of said container. The oil was then neutralized with caustic soda or some similar alkali and the process subsequently.

finished in much the same manner as previously cited in the treatment of the lighter distillates. This process necessitates the consumption of a'considerable period of time between that of bringing the acid in ing off of the resins before neutralization. During this period the oil is badly damaged. in respect to its color by its prolonged standing in intimate contact, first, withthat portion of the sulfuric acid which was not utilized in the above mentioned reaction; second, with certain products of dissociation of sulfuric acid; third, with the resins themselves. This process also necessitates the neutralizing of the oil by caustic soda ,or some other similar alkaliwhile a large duce alubricating oil of a. lighter, clearer and more highly translucent 'color, which object I accomplish by preserving to a'substantial degree the color that, the oil would have if the beneficial effects of the addition contact with the oil and that of the drawof sulfuric acid could be retained without the discoloration which the acid producesduring 'sedimentation and before neutralization. That is, I have discovered that if the collection and precipitation of the sulfonic compounds can be more thoroughly effected without sole reliance being placed upon the removal of the impurities by-sedimentation immediately after the sulfuric acid treatment, the discoloration of the oil by the acid will be minimized. 'I have further discovered that tlieremoval of these impurities can be accomplished by passing through the mixture of oil and acid, am?

with water. The process is also operative to effect,.to some extent, the attainment of the results sought if such precipitate which readily forms after mixing is drawn off be fore the ammonia gas is introduced. If,

I however, before the ammonia gas treatment,

' precisecolor which it is desired to obtain process being thus a continuous one.

--the mixture of oil and acid is allowed to stand until precipitation has entirely ceased and the sludge acid then drawn off, the acid, dissociation products and resins will have acted during precipitation, as heretofore, to discolor the oils. .It is not, therefore, de sirable to delay the ammonia gas treatment until this stage of the process, but even if then applied, it will be of some advantage in that it will stop the discoloring action of the sulfur dioxid, will precipitate the .remainin resins and preventthem from being dissolved in the oil and thus avoid a further lossof color.

Preferably the gas is introduced near the bottom of the oil tank, after which it is carried around and again passed through the liquid until absorption is completed, It he he ammonia causes the particles of sulfonic compounds or what is known in the art as resins, to become sticky and soapy and to coalesce into comparatively large units which are readily precipitated.

. The amount of acid and ammonia gas to in the finished product. Thus to one barrel (42 gallons) of oil may be added from five to fifty pounds of sulfuric acid (say, by weight, from less than one per cent. to seven per cent. or over of the oil.) The agitation of the oiland acidshould be continued for about an hour. The amount of ammonia gas will vary with what is required to collect all the resins, if it be desired to effect their complete removal. This amount will vary, by weight, fromone eighth to one per cent. ofthe oil. In estimating the weight of the ammoniaigas, I compressed the gas into a. liquid and allowed the gas to evolve by repose, caustic soda is satisfactory.

moving the pressure, The difierence between the weight of vthe liquid before and after the operation represented the weight of the gas. lVhile the ammonia has, of course, a neutrallzmg actlon, the step 1nvolvmg 1ts use 15 not a neutrahzmg step except incidentally, its main purpose being to preserve the colorof the oil,which heretofore has not been accomplished by the alkaline treatment. lVhile the precise reason why the avoidance or very material reduction of discoloration is accomplished cannot be stated with certainty, it is believed to be due, first, to the comparatively, rapid and effectual neutralization of the sulfur dioxid liberated after the addition of the' sulfuric acid, and second, to the collection and precipitation of all the resins and sulfonic compounds.

Again, the addition of ammonia in quantities suflicientto'effect the collection and precipitation of the resins is not si'lfficient to completely neutralize the acid and eliminate it from the oil and therefore it is necessary to follow the treatment just described by adding an alkali to the oil. For this pur- Before the caustic soda is added the mixture of oil and acid, after the ammonia gas treatment, should be allowed to remain quiescent until precipitation is completed and the oil then drawn off.

Instead of using caustic sodaor some other available and comparatively inexpensive alkali, it may be found entirely practic able and economical, owing to the saving-- of time and other considerations, to effect finalneutralization by continuing the application of ammonia gas after its color. preservative action has been completed,in which case it is not absolutely necessary to draw off the sulfonic compounds before neutralization. In other words, the color preservative step and the neutralizing step" may merge one into the other, thereby simplifying and expediting the refining operation.

In the final step the oil is passed through a centrifuge to effect the elimination, as completely as is practicable or necessary, of the salts and soaps remaining in the oil. The same effect may be produced, in a less thorough manner and muchless expeditiously, by settling. Or steam may be driven through the oil to boil off the water and the salts subsequently removed by centrifugal. force or by settling; v

Instead of using-ammonia gas, aqua. ammonia .may be used, but with much less satisfactory results, and where ammonia percentage of asphaltic material, and the 'high .viscosity oils which it contains. The

crude oil is placed in a. large still, under which fire is applied. Distillation of the lighter products then takes place, and later, at a higper temperature, the heavier products, or ubricating oils are distilled. It is this heavier product whichis'placed inthe agitator hereinafter described, to which isf added the; amount of acid hereinbefore specified.

The execution of the process is not dependent on the employment of any particular apparatus, but the essential steps of the process may be conveniently carried out in an apparatus like that illustrated in the accompanying. drawing, which is a diagram of the generator, the separator, the cooler,

the agitator, and connections.

' In the generator a is placed the ammonia water which is heated to generate the zlmmonia gas by means of steam coils b. By means of a rotary pump a and pipe connections d the gas is drawn into a separating tank 6, in which any water which has been carried over with the'ammonia settles and is drawn od from time to time through a. cock 7 at the bottom of the tank. The

ammonia gas is forced out of the top of the tank through a coil 9 in a tank It filled with water, which cools the ammonia gas and condenses any water therein, the water dropping down'into the separatin tank e. The ammoniagas then emerges rom the top of the cooler and is forced over and down through a pipe 2' the end of which ex-l tends into the bottom of the agitator and is provided with small perforations through which the gas escapes into the mixture of oil and acid in the agitator is. From the agitator anygas which has not been consume-d, passes through the pipe j back to the generator a, whence, together with other gases generated by the ammonia water, it

. passes again eventually to the agitator.

The agitator may be providw at the bottom with a pipe connection m to allow admission of air, and at the top with a pipe at for the admission of acid.

While, to the extent hereinbefore stated,

the employment of ammonia as an acid neutralizing agent and as a substitute for caustic soda in the treatment of illuminating oil distillates,.is not unknown, and while even ammonia gas has been suggested for use in connection with sulfurous acid, as a substitute' for sulfuric acid and caustic soda, and

also as one of several alkalis that may follow the. use of oxygen in the distillation of crude petroleum, it will be apparent, from the foregoing description, that. not'only do 1 specify thev employment of aonia gas in connection with the refining of a petroleum distillate in which the employment of ammonia in any form has not been heretofore suggested, and not only is the ammonia gas added for a purpose not heretofore contemplated, but it is added at such time and in such manner as to perform a function only requirement being that the sulfuric acid shall be neutralized; and as ammonia and caustic soda both perform this function, they may be said to be equivalents. But in the treatment of lubricating oils the ammonia, even when added in quantities not sufiicien't to completely neutralize the acid. prevents or materially reduces discoloration. as hereinbefore explained, which is a function which caustic soda does not and cannot perform, and therefore caustic soda is not an equivalent of ammonia.

While I have spoken of the distillates adapted for illuminating oils and lubricating oils as respectively light and heavy, it will be understood that'these terms are applicable only in comparing distillates fromfthe same crude oil, it being well known that the distillates adapted for lubricating oils of some crude oils are as light as the distillates adapted for burning or illuminating oils of other crude oils. lit is also well known that the quality of the distillate that strument at a temperature of degrees F.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is:

1. The process of purifying those petroleum distillates and reduced petroleum distillates adapted for use as lubricating oils which consists in first treating the distillate with sulfuric acid, and then, without permitting complete settlement, subjecting the 'mixture to the action of ammonia to minimize the coloring efiect of the acid in the subsequently finished product.

2. The process of purifying those petroleum distillates and reduced petroleum distillates adaptedfor use as lubricating oils which consists in first thoroughly mixing the distillate with sulfuric acid, and then, before permitting substantial settlement,

which consists in first treating the distillate,

' with sulfuric acid, then, without permitting complete settlement, subjecting the oil to a color preservative action by the addition of ammonia, then allowing settlement and sep arating the precipitate, and then further neutralizing the acid byjtreating the oil with an alkali. v

4. The process of purifying those petroleum distillates and reduced petroleum distillates adapted for use as lubricating oils which consists in first treating the distillate with sulfuricacid, and then, without permitting' complete settlement, subjecting the mixture to the action of ammonia to collect the sulfonic compounds,'thereby effecting their more complete ultimate removal, then allowing settlement and'separating'the precipitate, and then subjecting the oil to the action of an alkali to complete the neutrali-t zation of the acid. Y

5. The rocess of purifying those petroleum distillates and reduced petroleum distillates adapted for use as; lubricating oils which consists in first treating the distilthe mixture to the action ofammonia gas.

6. The process of purifying those petroleum distillates and reduced petroleum dismonia gas. L

tillates adapted for use as lubricating oils which conslsts in first thoroughly mixing the distillate with sulfuric a'cid,-and then, before permitting substantial settlement, subjecting the mixture to the action of am- 7. The process of purifying those petroleum distillates and reduced petroleum.dis-

tillates adapted for use as lubricating oils which consists in adding to the distillate sulfuric acid and, before allowing substantial settlement, passing through the mixture ammonia gas, and then further neutralizing the acid by treating the oil with an alkali.

8. The process "of purifying those pet'ro leum distillates and-reduced petroleum distillates adapted for use as lubricating oils which consists in first treating the distillate with sulfuric acid, then, without permitting complete settlement, passing through the mixture ammonia gas, and then subjecting the oil to'the-action of an alkali to complete the neutralization of the acid. 4

9. The process of purifying those petrooff the water and eliminating the salts sus J6" pended intheoil. 10. The process of purifying .those petroleum distillates and reduced petroleum distillates adapted for use as lubricating oils which consists in first thoroughly mixing :the distillate with sulfuric acid, then, withlates with sulfuric v acid, and then, without permitting complete settlement, subjecting.-

out permitting any substantial amount of settlement; causing ammonia gas to pass through the mixture until the sulfonic compounds or resins are collected, then draining ofl? the precipitate, and then completing neutralization by subjecting the oil to the action of caustic soda.

In testimony of which invention, I have hereunto set my hand, at Chester, on this 16th day of July, 1915.

v HAROLD T. MAITLAND. Witnesses: c

J. HOWARD PEW,

F. M. BROWN. 

